2 ms·

I disagree with this. I remember when I was in primary school and I was confused about how to multiply decimals. At that level I didn't even know what it would

I disagree with this. I remember when I was in primary school and I was confused about how to multiply decimals. At that level I didn't even know what it would mean to multiply a decimal: how can you have 5, 0.2 times? I asked the teacher and instead of explaining the concept properly, i.e. 0.5 is half etc., I was just told to multiply the other way around, by adding up 0.2, 5 times - and do drills with that. It's this kind of teaching that makes good robots and terrible mathematicians. (Thankfully I'm neither the former not the latter.)

aswanson 10y ago
That was a good way to teach you commutativity, though.
blahblah3 10y ago
Well properly understanding why certain number systems work (fractions, negative numbers) requires some understanding of set theory, and the great mathematicians of the past struggled with a lot of these concepts we take for granted (negative numbers, complex numbers). It's unrealistic to expect high school teachers to understand these foundations.